Trim fat from steak. Score both sides of steak in a diamond pattern by making shallow diagonal cuts at 1-inch intervals. Place steak in a plastic bag set in a shallow dish. For marinade, in a small bowl combine balsamic vinegar, olive oil, honey, oregano, sage, bouillon granules, and black pepper. Pour half of the marinade over the steak; seal bag. Set remaining marinade aside. Marinate in refrigerator for at least 2 hours or up to 24 hours, turning bag occasionally.

In a large nonstick skillet combine onions and reserved marinade. Bring to boiling; reduce heat to medium-low. Simmer, covered, for 13 to 15 minutes or until onions are tender, stirring occasionally. Add sweet pepper strips; cook, uncovered, over medium-high heat for 4 to 5 minutes or until pepper strips are crisp-tender, stirring constantly.

Drain steak, reserving marinade. Place steak on the rack of an uncovered grill directly over medium coals. Grill for 17 to 21 minutes or until medium doneness (160 degree F), turning and brushing once with reserved marinade halfway through grilling. Discard any remaining marinade.

To serve, thinly slice steak diagonally across the grain. Serve steak strips in warm tortillas. Top with the onion mixture. Makes 8 servings.

To warm tortillas, wrap in foil and place alongside steak on grill; grill about 10 minutes or until heated through, turning occasionally. (Or wrap in waxed paper or microwave-safe paper towels; microwave on 100 percent power [high] for 30 to 60 seconds.)